JPS59178475A - Device for blade cleaning of electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To prevent damage of a photosensitive body due to blade pressure and dust-like staining of a copy with a toner by detecting the surface temp. of a photosensitive body, releasing the blade pressure when it reaches a prescribed temp., and separating the blade from the body. CONSTITUTION:The pivot 12 of an arm 11 is turnably supported at the prescribed position of the outer circumference of a photosensitive body 10, a blade 13 is fixed to the top of the arm 11, and the rear end of the arm 11 is pressed with a spring 15 by action of a pressing solenoid 14, and the top edge 13a of the blade 13 comes in contact with the body 10 in a prescribed pressure. A back spring 16 is fixed to the rear end of the arm 11. A temp. sensor 17 is arranged at the circumference of the body 10 near the blade 13, and an output signal of the sensor resulting from the detection of the prescribed temp. is applied to a controller 18, and it produces a release signal to turn off the solenoid 14.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a blade cleaning device for an electrophotographic copying machine.

(Prior art) A blade cleaning device that scrapes off toner adhering to the surface of the photoreceptor by pressing a blade against the surface of the photoreceptor, as shown in FIG. The accumulated toner 3 is blocked by the tip edge 2a of the blade 2, and is collected on the upstream side of the edge 2a and deposited in a Δ shape. Next, when the blade 2 is off, the edge 2α of the blade 2 is slightly separated from the surface of the photoreceptor 1, as shown in FIG. 2, and a portion of the deposited toner 3 flows around to the downstream side of the edge 2a.

Therefore, when the blade 2 is turned on again, a small amount of toner 3' adheres to the downstream side of the edge 2a of the blade 2, as shown in FIG. When copying is performed in this state, a small amount of the toner 3' adheres to the portion of the photoreceptor 1 where charging has started, resulting in dust-like toner adhesion on the first copy as shown in FIG. Charging on timing is 20 to 3 minutes before image formation
It starts with 0 breath, and the dusty dirt part is πR-(20~30
) mm position. Experimentally, it only appears on the first copy, and because the amount is small, it disappears on the second and subsequent copies.

In order to eliminate the above-mentioned drawbacks, it was considered that the pressing force of the blade in pressure contact with the photoreceptor was not released even after copying was completed, as shown in Japanese Utility Model Application Publication No. 57-110570, but it was considered that the pressure of the blade in pressure contact with the photoconductor was not released even after the copying was completed, but it was considered that the pressure of the blade that was in pressure contact with the photoreceptor was not released even after copying was completed, When the temperature of the photoreceptor exceeds a predetermined temperature under normal usage conditions, the photoreceptor will be scratched by the blade pressure as shown in Figure 4, and if dust is generated, black streaks will appear on the plate copy. .

Furthermore, as shown in Japanese Patent Application Laid-Open No. 54-151043, it is also possible to strengthen a part of the photoconductor and press the blade against the reinforced section when the copying machine is stopped to prevent scratches on the photoconductor. However, there were drawbacks in that timing control was difficult and the diameter of the photoreceptor could not be made smaller.

In addition, since the copying machine stop layer blade is located approximately from the surface of the photoreceptor, it is difficult to adjust the separation distance, it is susceptible to temperature expansion, and the blades have poor compatibility.

(Purpose) The present invention prevents scratches on the photoconductor due to plate pressure, and makes subtle adjustments to separate the blade from the photoconductor surface by a small amount. The purpose is to reliably prevent soiling.

(Structure) It has been experimentally found that the pattern of scratches caused by a blade pressurized on the surface of a photoreceptor becomes extremely frequent when the temperature i of the photoreceptor becomes 88° C. or higher, as shown in FIG.

The present invention detects the surface temperature of the photoreceptor, and when the temperature reaches a certain level, releases the pressure and separates the blade from the photoreceptor, thereby eliminating the drawbacks of the conventional method.

FIG. 6 shows an embodiment of the present invention. IO is a photoreceptor, the shaft 12 of an arm 11 is pivotally mounted at a predetermined position on its outer circumference, a blade 18 is fixed to the tip of the arm 11, and the rear end of the arm 11 is pressurized by a pressure spring 15 by the operation of a pressure solenoid 14. The tip edge 13α of the blade 1B is pressed against the photoreceptor 10 with a predetermined pressure. 16 is a back spring attached to the rear end of the arm. Photoconductor 10 near blade 13
A temperature sensor 17 is disposed in the periphery, and an output signal based on detection of a predetermined temperature is applied to a control section 18, and a release signal from the control section 18 turns off the pressurizing solenoid 14.

Next, the effect will be explained. During copying, the pressurizing solenoid 14 is activated, and the arm 11 is activated via the pressurizing spring 15.
Rotate clockwise around shaft 12 as shown by the arrow, and rotate blade 1.
The edge 13a at the tip of 8 is pressed against the photoreceptor IO with a predetermined pressure. When the photoreceptor IO near the blade 18 reaches an abnormal temperature of about 38° C., the temperature sensor 17 detects this abnormal temperature and operates the control section 18 based on the output signal.
The pressurizing solenoid 14 is turned off in response to a release signal from 8, the pressurizing force is released, the arm 11 is rotated counterclockwise by the back spring 16, and the edge 18α at the tip of the blade 13 is separated from the surface of the photoreceptor 10.

The cancel signal is performed only after copying is completed, and is canceled by the copy start signal.

(Effects) According to the present invention, a temperature sensor is disposed around the photoreceptor, and when the temperature of the photoreceptor reaches a temperature at which it is damaged by the pressure applied by the blade, the temperature is detected, and the output signal is used to operate the control unit. Since the pressure of the blade pressure means is released in response to a release signal from Since the blade remains in pressure contact with the photoconductor even after copying is completed, toner accumulated on the upstream side of the blade does not go around to the downstream side of the blade.
Therefore, it is possible to prevent toner from adhering to the first copy at the start of copying, and there is no need for delicate adjustments such as separating the blade by a small amount from the surface of the photoreceptor.

[Brief explanation of the drawing]

Figure 1 is a front view of the blade tip when the blade is on, Figure 2 is a front view of the blade tip when the blade is off from Figure 1, and Figure 3 is a front view of the blade tip when the blade is off.
The figure is a front view of the tip of the blade when the plate is on as shown in Figure 2, Figure 4 is a plan view of a state where toner has adhered to the copy in the form of dust, and Figure 5 is a photoconductor surface due to the photoconductor surface temperature and blade pressure. FIG. 6 is a detailed front view of the present invention. 10... Photoreceptor, 18... Blade, ■4... Pressure solenoid, 15... Pressure spring, 16...
Back spring, 17...Temperature sensor, 18...
・Control unit.

Claims (1)

[Claims] ■ A pressurizing means for pressing the blade against the surface of the photoreceptor;
In a blade cleaning device configured to scrape off toner adhering to the surface of a photoreceptor, a temperature sensor is disposed around the photoreceptor, and the pressure means is activated by a release signal from a control section that is activated in response to an output signal from detection of a predetermined temperature. A blade cleaning device for an electrophotographic copying machine that releases pressure. (2) A blade cleaning device for an electrophotographic copying machine according to claim 1, wherein the release signal is issued only after copying is completed. (2) The above-mentioned cancellation signal is canceled by a copy start signal in claim 1. 3. A blade IJ cleaning device for an electrophotographic copying machine according to claim 2.